This invention relates to the provision of lubricant to the drive flat interface in a scroll compressor.
Scroll compressors are becoming widely utilized in refrigerant compression applications. In a scroll compressor, a first scroll member has a base and a generally spiral wrap extending from its base. A second scroll member has a base and a generally spiral wrap extending from its base. The wraps of the two scrolls interfit to define compression chambers. The second scroll member is caused to orbit relative to the first, and as the two orbit relative to each other, the size of the compression chambers decreases, compressing an entrapped refrigerant.
In one common type of scroll compressor, the orbiting movement of the second scroll member is caused by a rotating shaft having an eccentric pin. The eccentric pin interfits into a slider block, which is in turn received in a boss extending downwardly from the second scroll member. As the shaft rotates, its eccentric pin drives the slider block, and ultimately results in orbital movement of the second scroll member.
Typically, the eccentric pin has a drive flat surface which engages a mating flat surface in the slider block. For purposes of this application, the term xe2x80x9cflatxe2x80x9d should be understood to be generally flat. Preferably, a slight barrel shape is actually included into either of the two surfaces.
Applicant has seen slider blocks utilized in competitive scroll compressors that have a small notch adjacent a lower end. However, this small notch is not provided with structure between the slider block and the eccentric pin to assist in driving the lubricant along an interface surface between the two. As such, it would appear that the small notch would provide little if any lubrication benefit.
The components of scroll compressors, and in particular, the drive components, are desirably provided with lubricant during operation. However, one area that has been difficult to lubricate is this drive flat interface.
In the disclosed embodiment of this invention, a lubricant groove supplies a lubricant to the drive flat interface between a slider block and an eccentric pin in a scroll compressor. More particularly, a port is formed through the slider block to deliver lubricant from an area outwardly of the slider block to the internal bore of the slider block. The port is most preferably formed at a lower end of the slider block, and delivers the lubricant to a location in the bore in the slider block directly adjacent to the drive flat interface. There is structure between the slider block and the eccentric pin to assist in driving the lubricant from the notch along the interface surface. As will be explained in greater detail below, the contact surface between the slider block and the eccentric pin is made to be entirely on one side of an extension of a center point of the shaft perpendicular to the drive flat on the slider block. In this way, centrifugal forces will not block the flow of lubricant along the slider block pin interface. In one embodiment, this change is provided by the eccentric pin having a chamfered surface formed adjacent to its drive flat, and positioned adjacent to the outlet side of the lubricant notch. The chamfer ensures the entire contact between the drive flats will be on one side of the extension of the center point, and thus centrifugal force will drive the lubricant along that contact surface, and not block the flow.
In another embodiment, the eccentric pin could simply be shaped such that the entire contact will be on one side. One skilled in the design of scroll compressors would recognize that other trade-offs may come with such a design.
In this way, the chamfer provides a small reservoir such that lubricant exiting the port will gather and move to the drive flat interface.
These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.